Question

The molality of 1 M solution of sodium nitrate is 0.8 mol kg-!. Determine the density of the solution.
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Answer 1

Let the length of the cuboid =5x, breadth =3x, height =2x

Volume of a cuboid of length l, breadth b and height h =l×b×h
Given, volume of the cuboid =240cm
3

=>5x×3x×2x=240cm
3

=>x
3
=8
=>x=2
Hence, the length of the cuboid =5x=10cm, breadth =3x=6cm, height =2x=4cm
Total surface area of a cuboid of length l, breadth b and height h =2(l×b+b×h+l×h)
So, the total surface area of the cuboid with length =10cm, breadth =6cm and height =4cm=2(10×6+6×4+4×10)=2(60+24+40)=248cm
2